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UV Index in Iwakuni, Japan

Last updated: July 2, 2025

Understanding the UV Index is crucial for residents and visitors of Iwakuni, Japan, to protect their skin from the sun’s harmful rays. With UV levels soaring as high as 12 during peak hours, awareness of this metric can help prevent sunburn and promote long-term skin health. Iwakuni's Cfa climate—characterized by warm summers and mild winters—means that UV exposure can be significant throughout the year, making it essential to stay informed about daily UV levels. By keeping an eye on the UV Index, you can enjoy the beautiful outdoor scenery while safeguarding your skin from potential damage.

Hourly UV Index in Iwakuni

The UV Index throughout the day showcases a dynamic shift in sun intensity, peaking at 12 around noon. Beginning with a gentle 2 at 7:00 AM, the index steadily increases, hitting 11 by 11:00 AM as the sun climbs higher. By 12:00 PM, the sun reaches its zenith at 12, marking the highest UV exposure, making sun safety a priority. As the afternoon progresses, from 1:00 PM to 3:00 PM, the UV Index gradually decreases to 9 by 2:00 PM and 7 by 3:00 PM. The day winds down with a notable drop in intensity, returning to a mild 1 by 6:00 PM, emphasizing that the safest time to enjoy the sun is before noon or after 4:00 PM.

Average solar exposure data for the current time of the year. Actual values may vary and depend on many factors, such as cloud cover, vegetation cover, surface type, etc.
TimeUVICategoryTime to Burn
07:002low45 min
08:003moderate30 min
09:006high25 min
10:009very high15 min
11:0011extreme10 min
12:0012extreme10 min
13:0011extreme10 min
14:009very high15 min
15:007high25 min
16:004moderate30 min
17:002low45 min
18:001low45 min
19:001low45 min

Monthly UV Index Trends in Iwakuni

Throughout the year, UV Index levels exhibit significant seasonal variation, with the highest risks occurring in the spring and summer months. From March to August, the UV Index reaches extreme levels, peaking at 12 in July and August, where the recommended burn time is just 10 minutes. The months of April and May also maintain an extreme UV Index of 11. Conversely, during January and December, UV exposure is at a moderate level with a UV Index of 4, allowing for a burn time of 30 minutes. For residents and visitors, it is crucial to be particularly cautious from March through September, taking protective measures like wearing sunscreen, protective clothing, and limiting sun exposure during peak hours. Remain vigilant and prioritize skin safety, especially during the high-risk months of April through August.

Monthly Maximum UV Index for Iwakuni, Japan

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Iwakuni. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec468111111121210763
Data source: Statistical UV Index data for Iwakuni, based on information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

Compare Iwakuni UV Index with Other Japan Cities

The table above highlights how UV exposure in Iwakuni compares to other major locations across Japan. This comparison helps travelers and residents better understand regional sun intensity and plan outdoor activities with sun safety in mind.
Iwakuni's solar exposure compared to other cities in Japan. Generated using Copernicus Atmosphere Monitoring Service information.
 JanFebMarAprMayJunJulAugSepOctNovDec
Sapporo UVI2367999108532
Yokohama UVI35891111111110754
Tokyo UVI35891111111110754
Nagoya UVI468101111111110753
Osaka UVI468111111121110753
Iwakuni458111111121210764